20 g of hydrogen is present in 5 litre vessel. The molar concentration of hydrogen is

Options

A. 4
B. 1
C. 3
D. 2

Explanation

To find the molar concentration of hydrogen in the given scenario, we can follow these steps:

### Step 1: Determine the number of moles of hydrogen
We know that the number of moles can be calculated using the formula:

\[ \text{Number of moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}} \]

Given:
- Mass of hydrogen = 20 g
- Molar mass of hydrogen (H₂) = 2 g/mol

Calculating the number of moles:

\[ \text{Number of moles} = \frac{20 \, \text{g}}{2 \, \text{g/mol}} = 10 \, \text{moles} \]

### Step 2: Determine the volume in liters
The volume of the vessel is given as 5 liters.

### Step 3: Calculate the molar concentration
Molar concentration (C) is calculated using the formula:

\[ C = \frac{\text{Number of moles}}{\text{Volume (L)}} \]

Substituting the values we have:

\[ C = \frac{10 \, \text{moles}}{5 \, \text{L}} = 2 \, \text{mol/L} \]

### Final Answer
The molar concentration of hydrogen is **2 mol/L**.

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